Mara's Deck

The goal of crime scene processing is to collect the evidence and the scene context with as much precision as possible.

Crime repression and protection of personal liberty are the two that more closely relate to CSI because the police must investigate the crimes reported in ways that respect the laws and the liberties of those being interacted with.

Physical evidence is more objective because it is real and tangible so it cannot be denied while eye-witness testimony can be subject to influence of the situation, what others say, and the time between the event and the testimony being taken.

the interpretive value of evidence is more an issue of context than mere content.

The five ways in which context manifests itself in the crime scene are as follows: predictable effects, unpredictable effects, transitory effects, relational detail, and functional detail.

The four questions that an investigator should ask are as follows: What is it? What function did it serve? What relationship does it have to any other items of evidence or to the scene itself? What does it tell us about timing and sequencing aspects?

The forensic linkage triangle is the connection between the scene, subject, and victim using evidence gathered.

The five key ingredients are as follows: Knowledge, Skills and tools, A methodical approach, Flexibility, and a coordinated effort.

The three crime scene integrity issues are the addition of materials, the destruction of materials, and the movement of materials. Addition is when something that was not present during the crime is added such as a CSI creating a new shoe print. Destruction is when evidence at the scene is altered or destroyed, such as a shoe print being wiped up before it was recorded. Lastly, movement of materials can be moving the murder weapon from the ground to the table without documentation,

The CSI uses the standard of beyond a reasonable doubt because that is the court standard.

Class characteristics allow evidence to be compared to a group. Individual characteristics allow evidence to be compared to a specific person or object.

Short tandem repeat (STR) is the best for individualization because it combined with PCR but creates a better statistical discrimination than RFLP.

Tape is used to collect hair and fiber evidence by sticking the adhesive side down multiple times and then sticking the tape to a non-porous backing.

Fragments containing radial fractures within the first concentric fracture are used. The 4R rule (Ridges on Radial cracks are at Right angle to the Rear) is often applied to these fragments. By observing the ridge lines (Wallner lines) on the radial cracks, the direction from which the force was applied can be determined

The sequence and layering are used to compare paint samples.

The most significant form of environmental variation is the pollen located within the sample

The revolver keeps the cartridge case within the gun while pistols eject the cartridge into the scene

Riffling refers to the lands and grooves withing the barrel of the weapon.

Bullets are packaged individually in a fashion so that they do not move around when transported. The packaging should be marked with the item# and clear annotations as to where in the scene the item was recovered.

he whole tool mark should be taken when possible as the most important variation happens at a microscopic levels which can sometimes be missed when taking a casting.

The tread design is the most important class characteristic as a brand or model can be determined.

Unlined paint cans or glass jars are used to collect evidence at fire scenes.

Tracing lacks fluid movement and cannot be linked to a specific person while forged writing can be linked to a specific person.

If lacking training in computer crimes, the technician should contact a supporting computer crime team before attempting to seize the computer. Once they walk the tech through the appropriate shutdown procedure, the tech must document and note every action they proceed with as well as take photographs. Disconnect the power and adhesive label all cables so they can be reconfigured at the lab.

The primary goals are bringing the site under control and coordinating resources.

Document information provided means take the information given as it is given so that nothing gets changed when later recalled.
Not becoming a casualty means that officer safety is the number one priority when approaching a scene because the officer is of no help when they are injured.
Providing emergency care means providing care to those who need it at the scene.
Secure and control the scene and all those within it means that the scene should be sectioned off and any witnesses or those involved who do not need medical attention should be separated and kept in a safe environment till statements can be taken.
Release the scene to the appropriate authorities means the officer should be present at the scene till it is at a state to be handed over to the death investigators or CSI

The caller could list their own address rather than that of the one where the event occurred. If the address is not verified, it may cause the investigators to get a warrant for the caller's house rather than the address where the event occurred

Lifesaving care is a priority over evidence collection.

It is appropriate to slow or stop EMS from entering a crime scene when it is obvious that the person is deceased such as a decapitation.

They are concerned with documenting any dying declarations or utterances made by the victim and collecting any evidence that is removed from the victim

Bring them under control and isolate them so they can be identified and interviewed

The barrier should include the primary focal points, natural entry and exit points, and secondary scenes. Focal points are spots that investigators will naturally head to such as a body. Natural exit and entry points are the doors that the suspect is likely to have gone through when entering or exiting the scene. Secondary scenes are where the criminal may have loaded up goods or where weapons may have been dropped

A barrier such as a row of trees may seem like a space that is blocked off but the suspect may have run through them and if it is assumed that they didn't any evidence past that point may be contaminated due to it not being included in the crime scene boundary.

The purpose of a crime scene entry log is to record what time people entered and exited the crime scene and why they were at the scene. This should be put in place when the scene is secured

They should inform the crime scene team of everything they know, what they found, and what they did after they arrived at the scene.

Sequence is important because there is only one chance to process the scene in its original state.

Assessing, Observing, Documenting, Searching, Collecting, and Processing/analyzing.

Documentation such as road mapping blood stains has the ability to alter a scene.

It is important for a CSI technician to be able to return to a previous step as new evidence can be revealed when on later steps of the process. It is important to go back and process the newly revealed evidence from the start so that all information can be collected on it.

There is one Starbucks tumbler in an ombre of light teal at the base and deep teal at the top. It is plastic in construction and approximately 9 inches tall. It has a distinctive pattern of grooves, and the Starbucks logo imprinted on the side. The lid and base have slight cracks. It is located on a wooden table in the southeast quadrant of the table.

The first recheck is a visual check.

Photographs, sketching, feet and hands are bagged, physical examination, use of ALS, and records of body position and condition in addition to the state of the clothes.

Rechecks are conducted until they return a negative result. Meaning that everything has been collected.

The first debriefing happens at the crime scene upon the arrival of any new officers and CSI teams and is done by the first officer on scene.

The second debriefing happens at the scene before it is released. This is done by CSI to ensure that they have collected everything, this is done by using a investigative checklist.

The final debriefing happens within 24 hours of a crime scene being completed. This is done with all primary parties, the ME investigator if available, and initial responding officer if available. This is done at the station in most cases.

"In as pristine condition as possible" is important to CSI technicians because it helps prevent the unnecessary loss of evidence when active care is not being taken.

The primary concern of scene assessment is the scope of the scene, scene integrity, contamination control, team approach, search methods, and the need of PPE.

A single crime scene barrier is ineffective because it does not allow a buffer space for any evidence and the crowd of onlookers.

PPE can help control crime scene integrity because it helps avoid contamination but also deters people from entering the scene because they do not want to put on PPE.

The two approaches are the area approach, where a single team handles all activities related to processing, and the functional approach, where the team leader designates specific people to do specific tasks.

Single or multiple scenes affect the team composition because it is hard to transport specific groups or equipment so an area approach is often favored.

Availability of resources affects the team composition because there may be specifically trained people that are needed to process the scene which forces the functional team approach.

The size of a crime scene can force the area approach as it would take too long for a functional team approach to handle the whole scene. So the area approach is taken so that zones can be created and searched that way.

Circle/spiral search is when one person starts at the inside of a crime scene and slowly walks in a circle going out to the edge of the scene.

Strip/line search is when large scenes are being examined. There are strips separated and denoted with string. The searcher starts at one end of a string and searches down it till the end and then moves to the adjacent string a searches till all strips have been searched.

Grid search there are strips separated and denoted with string. The searcher starts at one end of a string and searches down it till the end and then moves to the adjacent string a searches till all strips have been searched. Then they do the same thing with a change of 90 degrees so that they are searching the same area but now in a perpendicular manner.

Zone search is where the scene is broken into multiple sections and the sections are then searched. This is commonly done on cars so that it is properly searched in its entirety.

Point-to-point search is where the focal points are looked at in order of importance.

The first variation is used in confined spaces where other search methods wouldn't work such as cars.

The second variation is with larger scenes where they are broken into multiple sections and then searched using traditional methods like strip, circle, or grid.

It is a problem because it can cause the transmission of life altering viruses and it can occur through contamination of crime scene equipment and clothing.

They should leave the scene till a team that is properly trained to handle the scene can make it safe for them to enter again.

It prevents confusion between multiple groups collecting evidence such as zone 1 using 1-45 to mark evidence while zone 2 uses A-Z to mark their evidence so that there is no confusion on where the evidence came from.

Notes
Photos/video
Sketches
Reports

If there are no establishing shots then there is no way for the viewer to understand what they are looking at.

A confusion problem may be created in a photograph if there is no identification on evidence in the case of two shells being present how are they supposed to determine which piece of evidence is of focus.

Overall photograph
Evidence establishing photographs
Evidence close-up/forensic quality photographs

Overall photographs depict the general conditions of the scene and the layout of the scene. It shows where landmarks are and the scene before any alterations.

This shows where evidence is located at a scene in relation to other items and landmarks.

The f-stop controls how much light is let into a shot by determining how wide the lens opens. The higher the f-stop the smaller the amount of light let in and the lower the f-stop the more amount of light let in.

The use of off-set flash, oblique lighting, or a ring light will correct the bleaching or overexposure of a shot.

One critical mistake is not letting the camera focus. This can be corrected by recording the item of interest for 10 seconds without movement.

Another critical mistake is having improper lighting. This can be corrected by setting up strong lighting in the scene.

The last critical mistake is recording with audio on. This can be corrected by turning the audio recording off at the time of filming.

The primary purpose of the crime scene sketch is to show the layout, orientation, and interrelationships of the scene and the evidence.

Heading
Diagram area
Legend
Title block
Scale and direction

Cross-projection is when it uses the traditional birds eye view but then laying down walls to depict evidence on vertical objects.

Elevation sketch shows a side view of a portion of the scene such as a interior wall or vertical structure.

It is done by measuring the right angles from the evidence to the surrounding walls and surfaces.

Triangulation of a cartridge casing is done by taking two measurements from a distinct landmark to two points on the casing and then taking two measurements from a different distinct landmark to two points on the casing.

Baseline mapping is most effective is exterior scenes lacking evident landmarks.

Rectangular coordinates on a grid are effective in large-scale scenes where there are no evident landmarks and multiple teams working such as gravesites.

Triangulation on a baseline is effective on exterior scenes where evidence is not to widely scattered but no evident landmarks.

The technology is not advanced enough to handle all types of scenes and standard scene documentation procedures.

The instrument cannot be aligned using a magnetic compass so it is more accurate to align by an angle.

Detailed, accurate, and understandable.

It is important to document investigative efforts that do not produce evidence, as the lack of documentation can be questioned in a court of law and be posed as if the technician did not do their job correctly, and that crucial evidence could be missing.

The notes created at the scene can be used to answer questions down the line that may not be answered in the final report.

Scene conditions, such as the stable and static conditions of the scene, like windows, doors, appliances, etc.

The condition of the scene is the state of cleanliness and descriptions of evidence.

It is allowable to evaluate the likelihood of an approach being used to enter or exit the scene.

Light can be converted to different wavelengths to see stains not visible to the naked eye. ALS/Fluorescence.

Broad band "blue light" is limited while ALS can have its wavelength changed.

Latent prints and latent foot/shoe prints

Gunpowder/soot and blood

Blue light (485-530nm)

Porous such as paper
Nonporous smooth such as glass
Nonporous rough such as vinyl
Special conditions such as human skin

Dusting the tape
Crystal violet, alcohol, and water process

It is used on large non-porous items such as walls and flooring. Fluorescent powders are used to generate a contrast upon the surface where the fingerprint is left. When an ALS is used in combination with the powder, one can bring the print itself forward off of a patterned surface. These powders are generally used when an item cannot be transported back to the lab as well.

The latent print reacts with the super glue and makes it harder for the print to be altered. This allows for safer transport and processing.

All glass and metal surfaces must be examined. Any surface with a significant amount of soot must be lightly brushed to see if there are any prints located below as the heat would have solidified the print.

The camera must be stable on a tripod.
Make sure it is angled at 90 degrees from the print and is square on it.
Place a scale in frame.
Take photos with flash on.
At N, S, W, and E and at a 45 degree angle photos are taken to show detail.

Almost any surface, floors, walls, doors, or other hard surfaces. However, it cannot be used on wet surfaces.

Used when impression is in loose soil, powder or sand.

Gently sift the dental stone onto the water till it becomes viscus, then add a form around and the dusting is continued till the mixture is achieved.

Adhesive or rubber lifters can only be used on nonporous smooth surfaces while gelatin lifters can be used on almost any surface including porous surfaces.

determine circumference of tire, lay paper in front of tire on a smooth, flat surface, spray exposed tire with cooking spray, continue spraying unexposed area as tire rolls forward, ensure one completely smooth circumference, drive off the paper, dust paper with magnetic powder

Photograph, prepare the impression removing obvious debris, prepare dental stone

It is the measurement between opposite side wheels.

The dental stone is poured on and around the impression, creating a pancake-like mass. The strength of the dental stone will suffice without requiring a deep pour. This is not true of plaster of paris. In that instance a form should be used and a deep pour of at least 2-inches.

It is similar to pancake batter.

Internal or interior ballistics
Terminal ballistics
External or exterior ballistics

Layering of trace evidence, indicative of the sequence of targets struck

Damage to the projectile, indicative of the type of target the bullet struck

Deformation of the projectile, indicative of a deflection along its flight path and the angle of the deflection

They are effective when determining from bullet holes in solid substrates as it will clearly limit the flight path of the bullet.

They are not very effective in humans as the body can twist and turn so there is no objective method of eliminating the majority of possible orientations.

Effective documentation of bullet defects is important because of the interrelationship between the defects and the location of items can allow for some understanding as to where the weapon was fired and where the victim was at the firing.

Horizontal angle or angle of departure: this is the angle of the muzzle in relation to the target using a horizontal reference line. It shows movement left or right and is measured using a protractor aligned with a horizontal plane.

Vertical angle or angle of elevation: this is the angle of the muzzle in relation to the target using a vertical reference line. It shows movement up or down and is measured using a protractor aligned with a vertical plane or the standard angle finder.

Cartridge- the complete unit of unfired ammunition composed of the bullet and casing.
Bullet is the subunit of the cartridge that is expelled.
Casing is the subunit of the cartridge that holds the primer and propellent.

The zone of possibility is the areas on the scene that are considered most probable, possible but awkward, and impossible for the shooter to be at at the time of the firing.

A penetrating bullet enters but does not exit
A perforating bullet enters and exits

The pinch point is where the bullet and metal first meet. This demonstrates the direction of travel for the bullet.

The wake effect is the fracture lines in the paint and on occasion in the metal itself, arcing out and away from the defect. This is in the opposite direction of the bullets path.

Become familiar with the scene.

Identifies the discrete patterns among the various bloodstained surfaces.

Classifies these patterns based on their physical characteristics using some form of established taxonomy.

Evaluates aspects of directionality and motion in the stain or pattern.

Evaluate angles of impact, points of convergence, and areas of origin (if necessary)

Evaluate interrelationships among stains, patterns, and other evidence.

Evaluates viable source events to explain the pattern (based on all of the above)

Validates the analysis through some form of peer review.

Spatter stains- where the primary stains are only circular or elliptical.

Non-spatter stains- where the primary stains are not circular or elliptical.

The shape of certain bloodstains provides indicators as to the direction of deposition as well as to the spatial origin of the blood.

The collapse of a free-flight droplet on a surface produces a stain with a circular or elliptical shape. These stains may have spines, scallops, or satellite stains. These characteristics, if present, may define the direction of travel for the droplet at the moment of impact.

By visualizing a line aligned with the directional angle and extended back into the scene for a number of related spatters, a point of convergence will form where the lines cross each other on a surface. The area of origin for the pattern would be located in three-dimensional space above the convergence point.

Color, Duration and Intensity

A positive will be blue green, start a few seconds after application and remain active for several minutes.

False positive (bleach) is immediate and intense but dies out quickly. Light green to white in color.

It is the difference of blood and forces acting on the blood. The pattern depends on the combination of the two.

With the majority of the visible light eliminated, the fabric appears white, while the blood, with its high IR absorbance, appears black.

Patterns that exhibit characteristics of more than one of the six mechanisms.

Detailed measurements of the location, size as well as description of the overall orientation of the patterns are necessary to be able to do any analysis.

Origin is the location where the fire started, and cause is what started the fire.

The scene can be affected by firefighters forcing entry, breaking windows, tearing down walls, or moving objects, in addition to any water damage caused by putting out the fire.

Char, smoke and soot, and damage patterns and v pattern.

The level of damage present, such as soot, smoke, and debris may mar, cover or destroy the fire patterns.

In addition structural damage, collapse, and lighting are often associated with fire scenes.

A waste-managed site is a landfill with detailed records of where and when loads were dropped in addition to each truck's tracks.

Compaction, heat produced, and hazards found in landfills.

It is likely that this technique would damage the body and any evidence.

Stratification is the basic concept of archeology where every layer is removed in the reverse order of deposition. This is why "keeping the dig in phase" is so important because every layer needs to be recorded and photographed along with any evidence.

Growth of the plants can be used to determine how long the plant has been growing which in turn can be used to determine how long the remains have been buried there.

Half are collected alive so they can mature while the other half are killed. Brushes and tweezers are used to collect larvae while adult flies and wasps are collected using a net.

head trauma, decapitation, major evisceration, massive blood loss, evident decomposition.

Liver mortis is the settling of the blood due to gravity after circulation stops.

Rigor mortis is the stiffening of the muscles after death.

The medical examiner has primary responsibility for estimating time of death.

Check the area beneath the body for fingerprints, DNA, foot or footwear marks. Front and back of both hands and feet should be examined carefully of trace evidence and then photographed. This is often an area that is overlooked.

The body is re-examined at the mortuary to document all wounds and to recover any artifacts in the body.

A person of the same gender is best qualified to examine a live target. For rape a S.A.N.E. nurse is the best person to conduct the examination.

An incised wound is longer than deep.
Stab wounds are deeper than they are long.

Entry wounds are typically symmetrical with an abrasion ring.
Exit wounds are asymmetrical and irregular.

The standard anatomical position is standing, arms at the side, palms facing outward. It is important to recognize that the ME describes wound paths based on the standard anatomical position. These descriptions relate the path to the body and nothing else. Bodies are typically not shot or wounded in the standard position so the ME description does not detail position of wounding.

The crime lab and the crime scene.

Context and interrelationship allow the connection of evidence to each other that allows true understanding of the scene.

Problem- define the investigative question
Hypothesis- identify viable explanations
Data- collect information to resolve the problem
Expect- identify what would be found if the hypothesis were true
Test- test the hypothesis against the evidence at the scene
Conclusion- identify an opinion and repeat for each variable.

It can be applied to reconstruct the entire scene or to resolve a specific investigative question.

There will only be a discrete amount of answers.

Absolute chronology refers to the actual time something happened like the call to 911. Relative chronology refers to the order in which events happened but not in relation to exact times.

They are snapshots of specific moments detaining a specific event in time.

The two possible results would be a match with the theory or the exclusion of the theory.

Chronology, superposition, and continuity.

It allows the investigator to create an objective picture of specific elements of the crime or incident.